Meshbesher says those witnesses, psychologists, and law enforcement personnel would have helped the jury to understand Smith's state of mind and understand the fear and pressure Smith was under when he killed 17-year-old Nick Brady and 18-year-old Haile Kifer inside his home on Thanksgiving Day of 2012 after it had been repeatedly burglarized.

In a case that drew national attention, jurors convicted Smith after three hours of deliberating, saying he went too far in repeatedly shooting the cousins after they no longer posed a threat.

Meshbesher says he will review hundreds of pages of courtroom transcripts in planning his appeal.

Smith was sentenced to life in prison in April for the killings.

Byron Smith, who has been charged with fatally shooting two teenagers who broke into his home on Thanksgiving Day in 2012, leaves the Morrison County Courthouse after closing arguments in his trial, Tuesday, April 29, 2014, in Little Falls, Minn.